Various braking or retarding mechanisms have been developed for gravity conveyors over the years. These include brake pads designed to be of a length and type sufficient to substantially reduce the rate of travel of the article. Another approach has been that of rollers equipped with one or more of various types of dampening mechanisms including those of the braking type and those of the inertial type. All of these mechanisms heretofore have been characterized by one of several deficiencies. The brake pad type has the problem of a gradually decreasing efficiency as the pads wear whereby the braking affect becomes less and less over a period of time, requiring monitoring and replacement with increasing frequency. Another problem has been that of lack of adjustability of the system to accommodate articles of various sizes and weight and, therefore, of different acceleration characteristics. The centrifugal type of braking mechanisms do not work properly on light weight articles. Those which have been most effective have also been generally complex and, therefore, costly. Those that rely upon a wheel as the retarding mechanism have proven to be sensitive to the irregularities of the bottom surface of the articles being conveyed. Also such equipment does have the problem of the limited area of contact between the wheel and the article. This tends to reduce the effectiveness of the braking mechanism as well as to materially increase the incident of wear on both the articles and on the braking mechanism. Another problem has been that if the retarding mechanism actually stopped the article there was no means of reinitiating its forward movement without the intervention such as by the article being hit by the next approaching article. This, in many cases is undesirable.